1. Field of the Invention
The present invention relates to a cable-stripping tool having two parts which can rotate relative to one another about an axis and of which a first part carries a cutting blade in the vicinity of the axis and a second part carries a hook which can move axially and which is biased towards an end position relative to the cutting blade by means of a first spring means. The hook has a concave side which faces towards the cutting blade and which functions to receive the cable to be stripped, and the hook also includes a generally axially oriented stem which is received in the tool.
U.S. Pat. No. 6,073,349 teaches a cable-stripping tool which comprises a first part and a second part that can be rotated relative to each other about an axis and of which the first part carries a cutting blade and the second part carries a hook. The hook is axially moveable and is biased towards an end position relative to the cutting blade by means of a first spring means, wherein the hook has a concave side that faces towards the cutting blade for receiving a cable to be stripped, and wherein the hook has a generally axially oriented stem which is received in the tool.
2. Description of the Related Art
In the case of the tool according to U.S. Pat. No. 6,073,349, the first part includes a handle that has a radial shoulder and that is biased by a spring peripherally in relation to the second part, so as to bias the shoulder into abutment with an attachment on the second part, wherein the attachment is displaceable axially and has two axially spaced abutment portions that lie in different circumferential positions and that can co-act with the shoulder to define respectively a first and a second position of rotation of the cutting blade relative to the hook.
The body also includes a further abutment, wherewith the handgrip can be twisted manually relative to the second part against the force of said spring, until the shoulder lies against said further abutment, which defines a third position of rotation.
The first and the second parts are returned to the first position of rotation as soon as the handgrip and the second part are released relative to each other. The positions of rotation correspond respectively to blade positions in which the blade is perpendicular to the axial direction of a cable to be stripped and received in the hook, a blade position which is inclined to the axial direction, and a blade position which is parallel with the axial direction.
One drawback with a tool of this known kind is that the first and second parts have mutually a rotational end position which must be maintained by continuous setting of torque manually and requiring manual procedures to be carried out in order to switch between the two remaining rotational positions.
A further drawback is that the body, and therewith the cutting blade, take two different positions of rotation when the tool is relieved of load.
Another drawback is that it is necessary to undertake comprehensive dismantling of the tool in order to change the hook.
Another drawback is that hook elements of mutually different effective lengths are not commercially available in respect of the tool.
One object of the invention is to provide a tool of the aforesaid kind with which the cutting blade can be set stably in pre-selected orientations relative to the body/hook, by manually twisting the handgrip relative to the body. A further object is to ensure that the blade will return to a predetermined position relative to the hook when the load on the hook is quickly relieved in an axial direction.
Yet a further object is to provide a tool construction that enables tool hooks to be easily exchanged, and to provide hooks of different effective lengths.
Still another object is to provide a tool construction in which the free end of the hook stem forms an instrument with which a hook element can be easily released from the tool.
These objects are achieved, either fully or partially, with a cable-stripping tool constructed in accordance with the invention.
According to an important feature of the invention, the tool includes a cam disc which is non-rotatably coupled to the first part and arranged for axial movement therealong. That side of the cam disc which lies proximal to the cutting blade has engagement formations disposed in spaced relationship around its periphery. A cam follower carried by the second part is able to co-act with said formations in order to set the blade in corresponding positions relative to the second part. A second spring means functions to axially bias the cam disc into contact with the cam follower at a pre-chosen force. A third spring means functions to rotatably bias the second part to a pre-selected position of rotation relative to the first part or handgrip, in which the blade may be perpendicular to a cable gripped by the hook.
The first part includes a hollow handgrip and a pin which is disposed centrally in the handgrip and which carries a cutting blade. The second part is a body which is rotatably mounted in the handgrip and which has a pin-receiving recess.
In one preferred embodiment, the hook element is adapted to be brought into contact with the cam disc, either directly or indirectly, through the medium of its spring when the hook element is released so that the cam disc will be displaced axially, at least briefly, and pass free from the cam follower. During this brief time period, the third spring means is able to twist/rotate the body and the handgrip to a predetermined, normal position.
The cam disc formations and the cam follower are by force and shape coupled, for instance by being rounded to enable the cam follower disc to be rotatably displaced relative to the cam follower by manually twisting the handgrip relative to the body, wherewith the second spring means functions to permit axial displacement of the cam disc on the one hand and to maintain the contact between the cam follower and the cam disc on the other hand, so as to hold the cam disc, and therewith also the cutting blade, in set positions against the action of the second spring means.
The stem portion of the hook is preferably received in a releasable latching arrangement on a carrier element which can be moved axially along the pin and which is secured against rotation relative to the body. The handgrip and the body have openings which, in the normal position of the cam disc relative to the body, are in alignment with each other and with a release latch in the latching device, whereby the latch can be released by inserting an instrument through the openings so as to enable the stem part of the hook to be withdrawn from the carrier element in conjunction with effecting a hook exchange. The tool includes associated exchange hooks or replacement hooks, and the free ends of respective hook stems each have the form of a pin which forms said instrument. The tool may also include a number of readily replaced hooks of mutually different effective lengths that adapt the tool to cables of mutually different diameters. The latches may be pretensioned towards latching positions, and the free stem-portion of the hook may have a wedge shape so as to move the latch away from its latching position when inserting the hook stem into the carrier element, until the latching element engages in a latching recess in the hook stem under the action of spring bias.
An inventive cable-stripping tool will now be described by way of example and with reference to the accompanying drawings.